As evidence mounts that excessive use of light is harming wildlife and adversely affecting human health, new initiatives in France and elsewhere are seeking to turn down the lights that flood an ever-growing part of the planet.

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Last month, France — including the City of Light — grew darker late at night as one of the world's most comprehensive lighting ordinances went into effect.

From 1 a.m. to 7 a.m., shop lights are being turned off, and lights inside office buildings must be extinguished within an hour of workers leaving the premises. The lighting on France’s building facades cannot be turned on before sunset. Over the next two years, regulations restricting lighting on billboards will go into effect. These rules are designed to eventually cut carbon dioxide emissions by 250,000 tons per year, save the equivalent of the annual energy consumption of 750,000 households, and slash the country’s overall energy bill by 200 million Euros ($266 million).But no less a motivation, says France’s Environment Ministry, is to "reduce the print of artificial lighting on the nocturnal environment" — a powerful acknowledgement that excessive use of lighting in many parts of the world is endangering our health and the health of the ecosystems on which we The good news is that light pollution is readily within our grasp to control. rely. The good news, however, is that light pollution is readily within our grasp to control.

Until recently, efforts to restrain our use of light have been primarily in response to the astronomical light pollution erasing starry nights. But researchers are increasingly focusing on the impacts of so-called ecological light pollution, warning that disrupting these natural patterns of light and dark, and thus the structures and functions of ecosystems, is having profound impacts.